Recording medium transport device and image forming apparatus

Abstract

Compared to a case where the protrusions extending from the outer surface of the belt member do not surround the holes provided in the belt member, the reduction in the adhesion force of the recording medium to the outer surface of the belt member caused by the provision of protrusions on the outer surface of the belt member is suppressed. [Solution] The protrusions 521 are provided so as to surround the hole 522. The hole 522 is surrounded by the protrusions 521 located around the hole 522, among the multiple protrusions 521 arranged in a grid pattern. Specifically, the hole 522 is taken in by the portion indicated by reference numeral 4A, the portion indicated by reference numeral 4B, the portion indicated by reference numeral 4C, and the portion indicated by reference numeral 4D of the protrusion 521.

Description

Technical Field

[0001] The present invention relates to a recording medium conveyance device and an image forming apparatus.

Background Art

[0002] Patent Document 1 discloses a configuration in which a through hole penetrating in the thickness direction and a convex portion protruding in the thickness direction on the belt conveyance surface side are provided on a belt body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a device for conveying a recording medium such as paper, for example, the recording medium may be conveyed in a state where the recording medium is attached to the outer peripheral surface of a circulating belt member. In this belt member, for example, suction holes are provided, and the recording medium is attracted to these holes, whereby the recording medium adheres to the belt member. Here, when a protruding portion is provided on the outer peripheral surface of the belt member, the contact area between the belt member and the recording medium can be reduced. On the other hand, in this case, there is a possibility that the recording medium is less likely to be attracted to the holes. When the recording medium is less likely to be attracted to the holes, the adhesion force of the recording medium to the outer peripheral surface of the belt member decreases. An object of the present invention is to suppress a decrease in the adhesion force of the recording medium to the outer peripheral surface of the belt member caused by providing a protruding portion on the outer peripheral surface of the belt member, as compared with a case where the protruding portion protruding from the outer peripheral surface of the belt member is not provided so as to surround the holes provided in the belt member.

Means for Solving the Problems

[0005] The invention described in claim 1 is a recording medium transport device comprising: a belt member that performs circulating movement, having a hole for allowing air to pass from the outer peripheral surface side to the inner peripheral surface side of the belt member, and transporting a recording medium attached to the outer peripheral surface; and a projection provided that protrudes from the outer peripheral surface of the belt member and is provided so as to surround the hole. The invention described in claim 2 is a recording medium transport device according to claim 1, wherein the protrusions are provided in a plurality and arranged in a grid pattern, and the hole is surrounded by the protrusions located around the hole among the plurality of protrusions arranged in a grid pattern. The invention described in claim 3 is a recording medium transport device according to claim 2, wherein each of the protrusions arranged in a grid pattern is positioned at an inclination with respect to the direction of movement of the belt member. The invention described in claim 4 is a recording medium transport device according to claim 1, wherein the outer circumferential surface of the belt member is provided with a plurality of annular protrusions as the protrusions, and the area of ​​the hole is smaller than the area of ​​the region surrounded by one of the annular protrusions. The invention described in claim 5 is a recording medium transport device according to claim 1, wherein the protrusion is provided in a linear shape and the width of the protrusion is 1.5 mm or less. The invention described in claim 6 is a recording medium transport device according to claim 5, wherein the protrusions are provided in a plurality and arranged in a grid pattern, extending in a common direction, and the distance between adjacent protrusions is 1.2 mm or more. The invention described in claim 7 is a recording medium transport device according to claim 1, wherein the protrusions are provided in a plurality and arranged in a grid pattern, extending in a common direction, and the distance between adjacent protrusions is greater than or equal to the value obtained by multiplying the width of the protrusion by 0.8. The invention described in claim 8 is a recording medium transport device according to claim 1, wherein the protrusions are provided in a plurality and arranged in a grid pattern, and the hole is surrounded by the protrusions located around the hole among the plurality of protrusions arranged in a grid pattern, and as the protrusions are arranged in a grid pattern, a plurality of rectangular protrusions are provided on the outer surface, and the area of ​​the region surrounded by the rectangular protrusions is 5% to 80% of the area of ​​the hole. The invention described in claim 9 is an image forming apparatus comprising: an image forming unit for forming an image on a recording medium; a heating device for heating the recording medium on which an image has been formed by the image forming unit; and a recording medium transport device for transporting the recording medium on which an image has been formed by the image forming unit to the heating device, or for transporting the recording medium that has passed through the heating device, wherein the recording medium transport device has the configuration of the recording medium transport device described in any one of claims 1 to 8. [Effects of the Invention]

[0006] According to the invention of claim 1, compared to a case where the protrusions protruding from the outer surface of the belt member do not surround the holes provided in the belt member, it is possible to suppress the reduction in the adhesion force of the recording medium to the outer surface of the belt member caused by providing protrusions on the outer surface of the belt member. According to the invention of claim 2, compared to the case in which the hole is taken in by a single annular projection, multiple projections can be positioned along the airflow path that is directed toward the hole, along the surface of the recording medium that faces the belt member, thereby suppressing a decrease in suction force caused by air from outside the space between the belt member and the recording medium being directed toward the hole. According to the invention of claim 3, compared to the case where the protrusion is aligned with the direction of movement of the belt member or the width direction of the belt member, the contact time between the member and the protrusion can be made longer when a member that contacts the outer surface of the belt member is provided. According to the invention of claim 4, the attractive force acting on the recording medium, which is the attractive force acting per unit area, can be increased compared to the case where the area of ​​the hole is larger than the area of ​​the region surrounded by one annular projection. According to the invention of claim 5, it is possible to reduce gloss unevenness that may occur in the image formed on the recording medium compared to the case where the width of the protruding portion exceeds 1.5 mm. According to the invention of claim 6, the gloss unevenness that may occur in the image formed on the recording medium can be reduced compared to the case where the distance between adjacent protrusions is less than 1.2 mm. According to the invention of claim 7, the gloss unevenness that may occur in the image formed on the recording medium can be reduced compared to the case where the distance between the protrusions is less than the value obtained by multiplying the width of the protrusions by 0.8. According to the invention of claim 8, compared to the case where the area of ​​the region surrounded by the protrusions is less than 5% of the area of ​​the hole, it is possible to reduce the gloss unevenness that may occur in the image formed on the recording medium, and compared to the case where the area of ​​the region surrounded by the protrusions exceeds 80% of the area of ​​the hole, it is possible to increase the adhesion force of the recording medium to the belt member. According to the invention of claim 9, compared to a case where the protrusions protruding from the outer surface of the belt member do not surround the holes provided in the belt member, it is possible to suppress the reduction in the adhesion force of the recording medium to the outer surface of the belt member caused by providing protrusions on the outer surface of the belt member. [Brief explanation of the drawing]

[0007] [Figure 1] This is a diagram showing an image forming apparatus. [Figure 2] This diagram shows the paper transport device as viewed from the direction indicated by arrow II in Figure 1. [Figure 3] This diagram shows the belt member as viewed from the direction indicated by arrow III in Figure 1. [Figure 4] This diagram shows a single hole and a magnified view of the area surrounding it. [Figure 5] This figure shows the cross-sectional state of the belt member along the VV line in Figure 4. [Figure 6] It is a figure showing the experimental results regarding gloss unevenness. [Figure 7] (A) to (E) are figures showing the results of an experiment regarding the relationship between the area of the hole part and the area of the protruding part. [Figure 8] It is a figure showing another configuration example of the belt member. [Figure 9] (A) and (B) are enlarged views of the paper conveyance device. [Figure 10] It is a figure showing the state of the cross section in the X-X line of Fig. 9(A). [Figure 11] (A) and (B) are figures showing an example of another shape of the protruding part. [Figure 12] It is a figure showing another configuration example of the belt member.

Mode for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a figure showing the image forming apparatus 100 according to the present embodiment. The image forming apparatus 100 is provided with an image forming unit 120 that forms an image on a sheet P which is an example of a recording medium. This image forming unit 120 is provided with a plurality of image forming units 200 that form an image to be transferred to a sheet P which is an example of a recording medium.

[0009] Each of the image forming units 200 has a photosensitive drum 11 as an example of an image holding body. Each of the image forming units 200 forms a toner image, which is an image to be transferred to the sheet P, on this photosensitive drum 11. Each of the image forming units 200 uses a dry developer to form a toner image on the photosensitive drum 11. Specifically, each of the image forming units 200 uses a powdery dry carrier and a powdery dry toner to form a toner image on the photosensitive drum 11. In this example, the carrier has a positive charging polarity. The toner has a negative charging polarity. Note that not only dry developers but also wet developers may be used.

[0010] Each of the image forming units 200 forms a toner image on the photoreceptor drum 11 using toners of different types. In the present embodiment, four image forming units 200, namely, the first image forming unit 200Y, the second image forming unit 200M, the third image forming unit 200C, and the fourth image forming unit 200K are provided.

[0011] In the moving direction of the intermediate transfer belt 15, the image forming units 200 are provided in the order of the first image forming unit 200Y, the second image forming unit 200M, the third image forming unit 200C, and the fourth image forming unit 200K. The first image forming unit 200Y forms a toner image using yellow toner. The second image forming unit 200M forms a toner image using magenta toner. The third image forming unit 200C forms a toner image using cyan toner. The fourth image forming unit 200K forms a toner image using black toner.

[0012] The image forming apparatus 100 is provided with an intermediate transfer belt 15 as an example of an intermediate transfer member. Further, the image forming apparatus 100 is provided with a primary transfer unit 10. The toner images formed by each of the image forming units 200 are transferred to the intermediate transfer belt 15 in the primary transfer unit 10. Furthermore, the image forming apparatus 100 is provided with a secondary transfer unit 20. The toner image transferred onto the intermediate transfer belt 15 is transferred to the paper P in the secondary transfer unit 20.

[0013] Also, the image forming apparatus 100 is provided with a fixing device 60. The fixing device 60 fixes the toner image transferred to the paper P onto this paper P. Furthermore, the image forming apparatus 100 is provided with a control unit 40. The control unit 40 includes a CPU that executes a program and controls each part within the image forming apparatus 100.

[0014] Furthermore, the image forming apparatus 100 is equipped with a display device 45 for displaying information to the user. The display device 45 consists of a display panel and the like. The display device 45 in this embodiment is composed of a touch panel. In addition to displaying information to the user, the display device 45 also receives instructions from the user. The display device 45 can also be considered as a receiving unit that receives instructions from the user.

[0015] Each image forming unit 200 is provided with a developing device 14. The developing device 14 deposits toner onto the surface of the photoreceptor drum 11. The developing device 14 makes the electrostatic latent image on the photoreceptor drum 11 visible using the toner. Furthermore, each of the image forming units 200 is provided with a charging device 12 for charging the photoreceptor drum 11. In addition, each of the image forming units 200 is provided with an exposure device 13 for forming an electrostatic latent image on the photoreceptor drum 11.

[0016] In each of the image forming units 200, the photoreceptor drum 11, which is an example of an image holder, rotates in the direction of arrow A. One example of an exposure apparatus 13 is a laser exposure unit that emits a laser. Another example of an exposure apparatus 13 is an exposure apparatus equipped with multiple light sources such as LEDs. In Figure 1, the light emitted from the exposure apparatus 13 is indicated by the symbol Bm.

[0017] Each image forming unit 200 is provided with a primary transfer roll 16. The location where the primary transfer roll 16 is installed is the primary transfer section 10. The toner image formed on the photoreceptor drum 11 is transferred to the intermediate transfer belt 15 in the primary transfer unit 10. Furthermore, each of the image forming units 200 is provided with a drum cleaner 17 to remove any developer remaining on the photoreceptor drum 11.

[0018] The intermediate transfer belt 15 moves in a predetermined direction in the direction of arrow B at a predetermined speed by a drive roll 31 driven by a motor (not shown). The primary transfer section 10 includes a primary transfer roll 16 that is positioned opposite the photoreceptor drum 11, with an intermediate transfer belt 15 in between. The toner image on the photoreceptor drum 11 is sequentially electrostatically attracted to the intermediate transfer belt 15. As a result, a superimposed toner image is formed on the intermediate transfer belt 15.

[0019] The secondary transfer section 20 is provided with a secondary transfer roll 22 and a backup roll 25. The secondary transfer roll 22 is positioned on the outer side of the intermediate transfer belt 15. The backup roll 25 is positioned on the inner side of the intermediate transfer belt 15. In this embodiment, the toner image transferred onto the intermediate transfer belt 15 is transferred to the paper P that has been transported to the secondary transfer unit 20.

[0020] The processing flow performed by the image forming apparatus 100 will be explained. The image forming apparatus 100 receives image data output from, for example, an image reading device (not shown) or a PC. The image forming apparatus 100 then performs image processing on this image data. As a result, image data corresponding to each of the multiple image forming units 200 is generated. Specifically, for example, image data for four colors—yellow, magenta, cyan, and black—is generated. The generated image data is output to the exposure device 13 provided in the image forming unit 200.

[0021] The exposure apparatus 13 irradiates the photoreceptor drum 11 with light emitted from, for example, a semiconductor laser, according to the input image data. In this embodiment, the surface of each photoreceptor drum 11 is charged by the charging device 12. Then, scanning exposure is performed on this surface by the exposure device 13. As a result, an electrostatic latent image is formed on the surface of the photoreceptor drum 11. Next, development is performed by the developing device 14, and a toner image is formed on the photoreceptor drum 11. This toner image is then transferred to the intermediate transfer belt 15 in the primary transfer unit 10.

[0022] After the toner image is transferred onto the intermediate transfer belt 15, this toner image moves to the secondary transfer section 20. The toner image moves to the secondary transfer section 20 by the intermediate transfer belt 15, which performs circulating movement. At this time, the paper P from the first paper storage section 53 and the second paper storage section 54 is transported to the secondary transfer section 20 by the transport roll 52, etc. Then, the toner image on the intermediate transfer belt 15 is electrostatically transferred all at once onto the paper P in the secondary transfer unit 20.

[0023] Subsequently, the paper P on which the toner image has been transferred moves from the secondary transfer unit 20 to the paper transport device 500. This paper transport device 500, which is an example of a recording medium transport device, transports the paper P to the fuser unit 60. The paper P, transported to the fuser 60, is heated by this fuser 60. The fuser 60 can be considered as a heating device. The fuser 60 also applies pressure to the paper P.

[0024] In this embodiment, the toner image on the paper P is fixed to the paper P by heating and pressurizing it. After that, the paper P is discharged from the image forming apparatus 100. The fixing device 60 is equipped with a fixing belt 61 that circulates and a heating source 62 that heats the fixing belt 61. Furthermore, the fixing device 60 is equipped with a pressure roll 63 that is pressed against the outer surface of the fixing belt 61. In the fixing device 60, the paper P passes between the fixing belt 61 and the pressure roll 63. During this passage, the paper P is heated and pressurized.

[0025] Figure 2 shows the paper transport device 500 as viewed from the direction indicated by arrow II in Figure 1. The paper transport device 500 is provided with a plurality of belt members 510. Specifically, four belt members 510 are provided. These four belt members 510 are arranged so that their positions are offset from each other in a direction perpendicular to the paper transport direction P. In this embodiment, each of the belt members 510 is formed in an annular shape. In other words, each of the belt members 510 is formed in an endless shape.

[0026] Each of the belt members 510 moves in a circulating manner. Each of the belt members 510 is provided in a flat shape and has an upper surface 511. In this embodiment, this upper surface 511 moves in the direction indicated by arrow 2A. The direction indicated by arrow 2A is the direction in which the paper P is transported. In the direction of transporting the paper P by the belt member 510, the fixing device 60 shown in Figure 1 is provided downstream of the belt member 510.

[0027] Furthermore, in this embodiment, a removal member 513 is provided to remove deposits adhering to the outer circumferential surface of the belt member 510. This removal member 513 is positioned in contact with the outer circumferential surface 510A of the belt member 510. The removal member 513 is composed of a brush. The removal member 513 removes deposits adhering to the outer surface 510A of the belt member 510. Examples of deposits include paper dust. A drive-rotating member 514 is provided inside the belt member 510. The drive-rotating member 514 rotates to provide the belt member 510 with a driving force for its movement. The drive-rotating member 514 rotates by receiving a driving force from a motor (not shown).

[0028] Furthermore, a driven rotating member 515 is provided inside the belt member 510. The driven rotating member 515 is positioned upstream of the drive rotating member 514 in the direction of transporting the paper P. The driven rotating member 515 supports the belt member 510 from the inside. The driven rotating member 515 receives force from the inner circumferential surface 510B of the belt member 510 and rotates in conjunction with the belt member 510. The inner circumferential surface 510B is shown in Figure 1. The removal member 513 is pressed against the driven rotating member 515 via the belt member 510. The removal member 513 rotates by receiving force from the belt member 510. The removal member 513 rotates driven by the belt member 510.

[0029] Each of the belt members 510 is provided with a hole. Note that the holes are not shown in Figure 2. In this embodiment, air flows from the outer circumferential surface 510A to the inner circumferential surface 510B of the belt member 510 through these holes. A suction device 516 is provided on the inside of the belt member 510. This suction device 516 draws air from the outer circumferential surface 510A side of the belt member 510. As a result, the air on the outer circumferential surface 510A side of the belt member 510 passes through the holes provided in the belt member 510 and moves toward the inner circumferential surface 510B side of the belt member 510. As a result, in this embodiment, the paper P is sucked in by the belt member 510, and the paper P adheres to the outer peripheral surface 510A of the belt member 510. The belt member 510 transports the paper P adhering to its outer surface 510A toward the fixing device 60.

[0030] Figure 3 shows the belt member 510 as viewed from the direction indicated by arrow III in Figure 1. In other words, Figure 3 is a front view of the belt member 510. Figure 3 shows one of the four belt members 510. The other three belt members 510 have the same configuration as this one belt member 510. The belt member 510 is provided with a protruding portion 521 that extends from the outer circumferential surface 510A of the belt member 510. Multiple protrusions 521 are provided. Each of the protrusions 521 is provided in a linear shape. Specifically, each of the protrusions 521 is provided in a straight line.

[0031] The belt member 510 has a flat upper surface 511 and a flat lower surface 512. The lower surface 512 is shown in Figure 1. In this embodiment, tension is applied to the belt member 510 by two rotating members, the driving rotating member 514 and the driven rotating member 515 shown in Figure 2. As a result, the belt member 510 in this embodiment is provided with a flat upper surface 511 and a flat lower surface 512.

[0032] On the upper surface 511, as shown in Figure 3, each of the protrusions 521 is provided in a straight line. In this embodiment, the protrusions 521 move as the belt member 510 moves. When the movable protrusions 521 are located on the upper surface 511, each of the protrusions 521 is arranged in a straight line.

[0033] Each of the protrusions 521 is positioned at an angle with respect to the belt movement direction, which is the direction in which the belt member 510 moves. In this embodiment, the protrusion 521 is provided as a first protrusion 521A and a second protrusion 521B, which have different inclination angles with respect to the direction of movement of the belt member 510. In this embodiment, the inclination angle θ1 of the first projection 521A with respect to the direction of movement of the belt member 510 is +45°. The inclination angle θ2 of the second projection 521B with respect to the direction of movement of the belt member 510 is -45°. In this embodiment, the first protrusion 521A and the second protrusion 521B are perpendicular to each other.

[0034] Furthermore, the inclination angle of the first protrusion 521A is not limited to +45°; it may also be +30° or +60°. The inclination angle of the first protrusion 521A may also be other than +45°. Similarly, the inclination angle of the second projection 521B is not limited to -45°, but may also be -30° or -60°. The inclination angle of the second projection 521B may be other than -45°. Furthermore, the inclination angle of the first protrusion 521A and the inclination angle of the second protrusion 521B may be different.

[0035] Multiple first protrusions 521A are provided and are arranged to extend in a common direction. The multiple first protrusions 521A extend in the direction indicated by arrow 3A, which is the common direction. The multiple first protrusions 521A are arranged so as to be parallel to each other. When the first protrusions 521A are located on the upper surface 511, the multiple first protrusions 521A are arranged so as to be parallel to each other. Furthermore, the first protrusion 521A is inclined to approach one end 510C in the width direction of the belt member 510 as it moves downstream in the direction of transporting the paper P.

[0036] Multiple second protrusions 521B are also provided. The second protrusions 521B are provided so as to extend in a direction different from the extension direction of the first protrusion 521A. Furthermore, the multiple second protrusions 521B are arranged to extend in a common direction. The multiple second protrusions 521B are arranged to extend in the direction indicated by arrow 3B, which is the common direction.

[0037] The multiple second protrusions 521B are arranged so as to be parallel to each other. When the second protrusions 521B are located on the upper surface 511, the multiple second protrusions 521B are arranged so as to be parallel to each other. The second protrusion 521B is inclined so as it moves downstream in the direction of transporting the paper P, it approaches the other end 510D in the width direction of the belt member 510.

[0038] In this embodiment, multiple first protrusions 521A and multiple second protrusions 521B are provided, each having different extension directions. As a result, in this embodiment, a grid-like arrangement of protrusions 521 is provided on the outer circumferential surface 510A of the belt member 510. In other words, in this embodiment, multiple protrusions 521 are arranged in a grid pattern. Furthermore, in this embodiment, the belt member 510 is provided with a hole 522. Air flowing from the outer circumferential surface 510A to the inner circumferential surface 510B of the belt member 510 passes through this hole 522.

[0039] In this embodiment, the multiple holes 522 are arranged in a manner aligned along the direction of belt movement. Furthermore, the multiple holes 522 are arranged in a manner aligned along the width direction of the belt member 510. The hole 522 is round. However, the shape of the hole 522 is not particularly limited. The shape of the hole 522 may also be elliptical or polygonal.

[0040] The first protrusion 521A and the second protrusion 521B may be provided in a manner that is not inclined with respect to the direction of belt movement. For example, one of the protrusions 521A and 521B may be provided in a direction aligned with the belt movement direction. Alternatively, the other protrusion 521 may be provided in a direction perpendicular to the belt movement direction. In this case as well, the multiple protrusions 521 are arranged in a grid pattern.

[0041] Figure 4 is a magnified view of one hole 522 and the area surrounding this hole 522. In this embodiment, the protrusion 521 is provided so as to surround the hole 522. In this embodiment, the hole 522 is surrounded by the projections 521 located around the hole 522, which are among the multiple projections 521 arranged in a grid pattern. Specifically, in this embodiment, the hole 522 is incorporated by the portion indicated by reference numeral 4A, 4B, 4C, and 4D of the protruding portion 521.

[0042] The portion indicated by reference numeral 4A is a part of one of the multiple first protrusions 521A, indicated by reference numeral 10A. The portion indicated by reference numeral 4B is another first protrusion 521A, which is a part of another first protrusion 521A indicated by reference numeral 10B, located on the opposite side of the hole 522 from the first first protrusion 521A. The portion indicated by reference numeral 4C is a part of one of the multiple second protrusions 521B, indicated by reference numeral 10C. The portion indicated by reference numeral 4D is another second protrusion 521B, which is located on the opposite side of the hole 522 from the first second protrusion 521B and is a part of the other second protrusion 521B indicated by reference numeral 10D.

[0043] Each of the first protrusion 521A and the second protrusion 521B has an intersection point 88 where it intersects with the other protrusion 521. The portion indicated by reference numeral 4A is the portion located between the two intersection points 88 of the first projection 521A indicated by reference numeral 10A. The portion indicated by reference numeral 4B is located between the two intersection points 88 of the other first protrusion 521A indicated by reference numeral 10B. The portion indicated by reference numeral 4C is the portion located between the two intersection points 88 of the first second projection 521B indicated by reference numeral 10C. The portion indicated by reference numeral 4D is located between the two intersection points 88 of the other second protrusion 521B indicated by reference numeral 10D.

[0044] In this embodiment, the hole 522 is surrounded by the protrusion 521, thereby ensuring that the paper P adheres to the belt member 510. Here, for example, let's consider a case where multiple cylindrical protrusions, for example, spaced apart from each other, are provided as projections 521 on the outer circumferential surface 510A of the belt member 510. In this case, air can move between these protrusions. In this case, air that enters the gap between the paper P and the belt member 510 from outside the gap moves between the protrusions and heads towards the hole 522. In this case, the suction force on the paper P decreases, and the adhesion force of the paper P to the belt member 510 decreases.

[0045] In contrast, in this embodiment, the hole 522 is surrounded by the protrusion 521. In this case, air outside the gap between the paper P and the belt member 510 is less likely to flow towards the hole 522. In this case, the adhesion force of the paper P to the belt member 510 is increased compared to a configuration in which the hole 522 is not surrounded by the protrusion 521.

[0046] Figure 5 shows the cross-sectional state of the belt member 510 along the VV line in Figure 4. Figure 5 shows the cross-sectional state of the belt member 510 in a plane perpendicular to the extension direction of the first projection 521A. In this embodiment, the cross-sectional shape of the first protrusion 521A and the cross-sectional shape of the second protrusion 521B are the same. Also, in this embodiment, the distance between adjacent first protrusions 521A and the distance between adjacent second protrusions 521B are equal.

[0047] In this embodiment, the width W of the protrusion 521 is 1.5 mm or less. In this embodiment, the projection 521 is provided in a linear shape as described above. In a direction perpendicular to the direction of extension of the linear projection 521, the width W of the projection 521 is 1.5 mm or less. This reduces the likelihood of problems caused by the paper P being heated by the belt member 510. Specifically, it reduces the likelihood of uneven gloss caused by the paper P being heated by the belt member 510.

[0048] In this embodiment, as shown in Figure 1, the belt member 510 of the paper transport device 500 is positioned opposite a portion 61A of the fixing belt 61 provided on the fixing device 60. In this case, the belt member 510 is heated by heat from the fixing device 60. When the belt member 510 is heated, the paper P is heated by the belt member 510 as it is transported by the belt member 510. In this case, if the belt member 510 is provided with holes 522, uneven heating of the paper P will occur. Consequently, uneven gloss will occur in the image on the paper P due to the difference in heating.

[0049] In this embodiment, the paper P has a portion facing the hole 522 that is not in contact with the belt member 510, and a portion that is in contact with the belt member 510. In this case, the degree of heating differs between the area opposite the hole and the area in contact with the belt. In this case, uneven gloss is more likely to occur in the image on the paper P. In contrast, as in this embodiment, if the belt member 510 is provided with linear protrusions 521, the area of ​​the belt contact portion is reduced, and uneven gloss becomes less noticeable. Furthermore, if the width W of the protruding portion 521 is 1.5 mm or less, the area of ​​the belt contact portion is further reduced, making uneven gloss even less noticeable.

[0050] Figure 6 shows the experimental results regarding gloss unevenness. In the experiment on gloss unevenness, several types of belt members 510 with different widths W of the protrusions 521 and spacing distances between the protrusions 521 were prepared. The degree to which gloss unevenness was noticeable was then examined for each belt member 510. As a result, in this embodiment, when the width W of the protrusion 521 is within 1.5 mm, the unevenness of gloss is not noticeable in some of the belt members 510. When the width W of the protruding portion 521 becomes 2.0 mm, uneven gloss becomes more noticeable in all types of belt members 510.

[0051] Here, the distance between the protruding portions 521 refers to the distance indicated by the reference numeral 5A in Figure 5. The separation distance between the protrusions 521 refers to the distance between protrusions 521 that are parallel to each other and adjacent to each other. In other words, the separation distance between the protrusions 521 refers to the distance between protrusions 521 that extend in a common direction and are adjacent to each other. More specifically, the spacing between the protrusions 521 refers to the distance between the end portion 521E in the width direction of one protrusion 521 and the end portion 521F in the width direction of another protrusion 521 located next to this protrusion 521. "The end portion 521E in the width direction of one protrusion 521" refers to the end portion located on the side closer to the other protrusion 521. Also, "the end portion 521F in the width direction of the other protrusion 521" refers to the end portion located on the side closer to one protrusion 521.

[0052] In this embodiment, as shown in Figure 6, when the width W of the protrusion 521 is within 1.5 mm and the separation distance is 1.2 mm or more, gloss unevenness is less noticeable under either condition. If the spacing distance is small, the protrusions 521 are arranged closely together, and the area of ​​the belt contact portion increases substantially. In this case, uneven gloss becomes more noticeable. In contrast, if the spacing distance is large, the protrusions 521 are arranged in a sparse manner. In this case, the area of ​​the belt contact portion decreases, and uneven gloss becomes less noticeable.

[0053] Furthermore, it is preferable that the distance between adjacent protrusions 521 be greater than or equal to the value obtained by multiplying the width W of the protrusion 521 by 0.8. For example, if the width W of the protrusion 521 is 0.6 mm, the value obtained by multiplying the width W of the protrusion 521 by 0.8 is 0.48 mm. In this embodiment, as shown by reference numeral 6A in Figure 6, the belt member 510 has a width W of 0.6 mm and a separation distance of 0.48 mm or more, and the gloss unevenness is no longer noticeable.

[0054] Furthermore, for example, if the width W of the protrusion 521 is 1.0 mm, the value obtained by multiplying the width W of the protrusion 521 by 0.8 will be 0.8 mm. In this embodiment, as indicated by reference numeral 6B, in a belt member 510 where the width W of the protrusion 521 is 1.0 mm and the separation distance is 0.8 mm or more, the unevenness of gloss becomes less noticeable. Furthermore, for example, if the width W of the protrusion 521 is 1.5 mm, the value obtained by multiplying the width W of the protrusion 521 by 0.8 will be 1.2 mm. In this embodiment, as indicated by reference numeral 6C, in the belt member 510 where the width W of the protrusion 521 is 1.5 mm and the separation distance is 1.2 mm or more, the unevenness of gloss is not noticeable.

[0055] Based on the above results, in this embodiment, it is preferable to satisfy at least one of the following three conditions, from the first to the third condition. More preferably, two conditions are met. Even more preferably, all three conditions are met. Condition 1: The width W of the protruding portion 521 shall be 1.5 mm or less. Second condition: The distance between adjacent protrusions 521 shall be 1.2 mm or more. Third condition: The distance between adjacent protrusions 521 shall be greater than or equal to the value obtained by multiplying the width W of the protrusion 521 by 0.8.

[0056] Next, we will explain the relationship between the area of ​​the hole 522 and the protrusion 521. In this embodiment, as described above, multiple protrusions 521 are provided. Furthermore, these multiple protrusions 521 are arranged in a grid pattern. Moreover, the hole 522 is surrounded by the protrusions 521 located around the hole 522 among the multiple protrusions 521 arranged in a grid pattern. In this embodiment, the protrusions 521 are arranged in a grid pattern, resulting in multiple rectangular protrusions 528 being provided on the outer peripheral surface 510A, as indicated by reference numeral 4F in Figure 4.

[0057] The multiple rectangular projections 528 are adjacent to one another. Furthermore, each of the multiple rectangular projections 528 is provided in contact with another adjacent rectangular projection 528. In other words, one rectangular projection 528 shares a portion located between two adjacent rectangular projections 528 at the intersection 88. In Figure 4, each of the parts indicated by reference numeral 4G is located between the intersection points 88. In Figure 4, each of the parts indicated by reference numeral 4G is shared between one rectangular projection 528 indicated by reference numeral 4F and four other rectangular projections 528 located around this one rectangular projection 528.

[0058] In this embodiment, experimental results showed that it is preferable to set the area of ​​the region enclosed by one of these rectangular protrusions 528 to 5% or more and 80% of the area of ​​the hole 522. The area enclosed by the rectangular projection 528 refers to the area inside the rectangle indicated by reference numeral 4H in Figure 4. More specifically, the area of ​​the region enclosed by the rectangular projection 528 refers to the area of ​​the region enclosed by a line along the extension direction of the projection 521 that passes through the center of the projection 521 in the width direction. This area should be between 5% and 80% of the area of ​​the hole 522. Hereinafter, in this specification, the area of ​​the region enclosed by the rectangular projection 528 will be referred to as the "projection area".

[0059] Figures 7(A) to 7(E) show the experimental results regarding the relationship between the area of ​​the hole 522 and the area of ​​the protruding part. Note that in Figures 7(A) to 7(E), the belt member 510 is shown tilted at 45°. In each of Figures 7, the direction indicated by arrow 7X in Figure 7(A) indicates the direction of movement of the belt member 510. Figure 7(A) shows the experimental results under the condition that the area of ​​the protruding portion is 1.3% of the area of ​​the hole portion 522. In Figure 7(A), the diameter of the hole 522 is 4 mm. Also in Figure 7(A), the length of one side 521L of the rectangular projection 528 is 0.4 mm.

[0060] Under this condition, multiple rectangular protrusions 528 are arranged closely together. In other words, under this condition, the protrusions 521 are arranged closely together. In this case, the area of ​​the belt contact portion, as explained above, will be larger. In this case, uneven gloss will be more noticeable. Furthermore, under the conditions shown in Figure 7(A), the adhesion force of the paper P to the belt member 510 is ensured. In this embodiment, as will be described later, the adhesion force of the paper P to the belt member 510 may decrease due to the provision of the protrusion 521. In contrast, under the conditions shown in Figure 7(A), a decrease in adhesion force is unlikely to occur.

[0061] Next, we will explain Figure 7(E). Figure 7(E) shows the experimental results under the condition that the area of ​​the protrusion is 110% of the area of ​​the hole 522. In Figure 7(E), the diameter of the hole 522 is 4 mm, and the length of one side 521L of the rectangular protrusion 528 is 3.72 mm. In this case, the multiple rectangular protrusions 528 are arranged in a sparse manner. In other words, the protrusions 521 are arranged in a sparse manner. In this case, the area of ​​contact between the protruding portion 521 and the paper P becomes smaller. In other words, the area of ​​the belt contact portion becomes smaller. In this case, the resulting unevenness in gloss becomes less noticeable.

[0062] On the other hand, in this case, the adhesion force of the paper P to the belt member 510 becomes smaller. In Figure 7(E), as indicated by arrows 1Y to 6Y, the air inside each of the multiple rectangular protrusions 528 is directed towards the hole 522. In the case of the rectangular protrusions 528 in which the hole 522 is located inside the protrusion 528, the air inside the protrusion 528 is drawn out. In this case, the suction force acting on the paper P, specifically the suction force acting per unit area, decreases. In this case, the adhesion force of the paper P to the belt member 510 decreases.

[0063] In the configuration example shown in Figure 7(E), the size of each rectangular projection 528 is large. In this case, the suction force acting on the paper P, specifically the suction force acting per unit area, decreases. As a result, in the configuration example shown in Figure 7(E), the adhesion force of the paper P to the belt member 510 decreases. As shown in Figure 7(E), it was found that when the area of ​​the protruding portion is 110% of the area of ​​the hole portion 522, the adhesion force of the paper P to the belt member 510 decreases.

[0064] In contrast, under the conditions shown in Figure 7(A), the area of ​​one rectangular projection 528 is small, and the volume of the space inside this rectangular projection 528 is small. In this case, the amount of air drawn out from inside each of the rectangular protrusions 528 decreases. The amount of air drawn out from inside each of the rectangular protrusions 528 with the holes 522 inside decreases. As a result, under the conditions shown in Figure 7(A), the decrease in the suction force acting on the paper P, specifically the suction force per unit area, is suppressed. In this case, the decrease in the adhesion force of the paper P to the belt member 510 is suppressed.

[0065] Figure 7(B) shows the experimental results under the condition that the area of ​​the protruding portion is 5% of the area of ​​the hole 522. Figure 7(C) shows the experimental results under the condition that the area of ​​the protruding portion is 26% of the area of ​​the hole 522. Figure 7(D) shows the experimental results under the condition that the area of ​​the protruding portion is 80% of the area of ​​the hole 522. Note that in Figures 7(B) to 7(D), the diameter of the hole 522 is 4 mm in all cases. Furthermore, in Figure 7(B), the length of one side 521L of the rectangular projection 528 is 0.8 mm. In Figure 7(C), the length of one side 521L of the rectangular projection 528 is 1.8 mm. Furthermore, in Figure 7(D), the length of one side 521L of the rectangular projection 528 is 3.17 mm.

[0066] In each of these three conditions, the multiple rectangular protrusions 528 are arranged in a sparse manner. In other words, the protrusions 521 are arranged in a sparse manner. In each of these three conditions, the area of ​​contact with the belt becomes smaller. In this case, uneven gloss becomes less noticeable. Furthermore, under each of these three conditions, the volume of the space inside one rectangular projection 528 is small. Under each of these three conditions, the decrease in the adhesion force of the paper P to the belt member 510 is suppressed.

[0067] Figure 8 shows another example of the configuration of the belt member 510. In this configuration example, as described above, a plurality of rectangular protrusions 528 are provided on the outer circumferential surface 510A of the belt member 510. The rectangular projection 528 is annular, and in this configuration example, it can be said that there are multiple annular projections 521. Furthermore, in this configuration example, a hole 522 is provided, as described above. In this configuration example shown in Figure 8, the area of ​​the hole 522 is smaller than the area of ​​the region surrounded by one annular projection 521.

[0068] In this configuration example shown in Figure 8, the protrusions 521 are arranged in a grid pattern, similar to the above. In this configuration example, the diameter of the hole 522 is smaller than the distance 521Y between adjacent protrusions 521. The adjacent projections 521 extend in a common direction. In this configuration, the diameter of the hole 522 is smaller than the distance 521Y between adjacent projections 521 that extend in a common direction.

[0069] Even in this configuration example, the decrease in the adhesion force of the paper P to the belt member 510 can be suppressed. In this configuration example, the air inside one annular projection 521 is directed toward one hole 522. In this case, compared to the case where the air inside multiple projections 521 is directed toward one hole 522, as described above, the decrease in the adhesion force of the paper P to the belt member 510 is suppressed.

[0070] It is conceivable that, during the manufacturing stage of the belt member 510, the positional relationship between the hole 522 and the protrusion 521 may not be controlled when the hole 522 and the protrusion 521 are provided. In this case, a single hole 522 may be positioned within the inner region of each of the multiple annular protrusions 521. In this case, the air inside each of the multiple annular protrusions 521 will be directed towards the single hole 522. However, even in this case, some of the other holes 522 among the many provided holes 522 are located inside the annular projection 521. In this case, the suction force of the paper P is increased at the locations where these other holes 522 are provided.

[0071] Figures 9(A) and (B) are enlarged views of the paper transport device 500. Figures 9(A) and 9(B) show the paper transport device 500 as viewed from the side. Figures 9(A) and 9(B) also show a simplified representation of the paper transport device 500. Furthermore, the projection 521 described above is omitted from the illustration in Figures 9(A) and 9(B). Figure 9(A) shows the paper transport device 500 described above. Figure 9(B) shows another example of the configuration of the paper transport device 500.

[0072] As described above, and as shown in Figure 9(A), the belt member 510 is arranged in a flattened shape and has an upper surface 511 and a lower surface 512. In this embodiment, the belt member 510 moves in a circular motion such that the upper surface 511 moves in the direction indicated by arrow 9A. Furthermore, in this embodiment, as described above, a removal member 513 is provided for removing deposits adhering to the outer peripheral surface 510A of the belt member 510. The removal member 513 is positioned in contact with the outer circumferential surface 510A of the belt member 510. The removal member 513 is composed of a brush.

[0073] A driven rotating member 515 is provided inside the belt member 510. The driven rotating member 515 is positioned upstream of the drive rotating member 514 in the direction of transporting the paper P. The driven rotating member 515 receives force from the inner circumferential surface 510B of the belt member 510 and rotates in conjunction with the belt member 510. The removal member 513 is pressed against the driven rotating member 515 via the belt member 510. The removal member 513 is in contact with the outer circumferential surface 510A of the belt member 510. The removal member 513 rotates in response to the force from the belt member 510.

[0074] In this embodiment, the fixing device 60 shown in Figure 1 is provided downstream of the belt member 510 in the direction of conveying the paper P by the belt member 510. The removal member 513 contacts the portion 510H of the belt member 510 that is located on the side opposite to the fixing device 60. The belt member 510 has a portion 510T located on the fixing device 60 side and a portion 510H located on the opposite side from the fixing device 60 side. The removal member 513 contacts the portion 510H located on the opposite side.

[0075] The belt member 510 has one end 510S and the other end 510V, which are located at different positions in the direction of transporting the paper P. One end 510S is located on the side of the fixing device 60, and the other end 510V is located on the opposite side from the fixing device 60. The removal member 513 is located on the other end 510V side of the belt member 510. Furthermore, the removal member 513 is pressed against the driven rotating member 515 via the belt member 510.

[0076] Here, we assume that the removal member 513 is provided on the fixing device 60 side, as shown in Figure 9(B). In this case, heat from the fixing device 60 is more likely to act on the removal member 513. When heat from the fixing device 60 acts on the removal member 513, the material to be removed that is attached to the removal member 513 is more likely to adhere to the removal member 513. The removal member 513 accumulates the material removed from the belt member 510. If the removal member 513 is located on the fixing device 60 side, this material is more likely to adhere to the removal member 513. In contrast, as shown in Figure 9(A), if the removal member 513 is provided on the side opposite to the fixing device 60, this adhesion becomes less likely to occur.

[0077] In this embodiment, as shown in Figure 9(A), a drive rotating member 514 having the function of feeding out the belt member 510 is provided on the fixing device 60 side. Therefore, on the fixing device 60 side, slack in the belt member 510 is less likely to occur compared to the side where the driven rotating member 515 is provided. By installing the removal member 513 on the fixing device 60 side, the removal member 513 can be brought into contact with the belt member 510, which is in a state with minimal slack. In this case, uneven cleaning is reduced. However, in this case, as described above, the material to be removed attached to the removal member 513 tends to become fixed to the removal member 513. Therefore, in this embodiment, as described above, the removal member 513 is provided on the side opposite to the fixing device 60.

[0078] In this embodiment, the removal member 513 is provided on the side opposite to the fixing device 60, which makes it less likely for uneven cleaning to occur. In this embodiment, as described above, a protrusion 521 is provided on the outer circumferential surface 510A of the belt member 510. In this embodiment, this protrusion 521 makes it less likely for uneven cleaning to occur. In a configuration without the protrusion 521, cleaning of the entire surface of the belt member 510 is required. In this case, uneven cleaning is likely to occur. In contrast, in this embodiment, the protruding portion 521 becomes the target of cleaning, reducing the area of ​​the part that needs cleaning. In this case, compared to when cleaning is required over the entire surface of the belt member 510, uneven cleaning is less likely to occur.

[0079] Figure 10 shows the cross-sectional state along line XX in Figure 9(A). Note that the driven rotating member 515 is not shown in Figure 10. When a protrusion 521 is provided on the belt member 510, the fibers 513S that make up the removal member 513, which is made of a brush, come into contact with the top of the protrusion 521. Furthermore, the fibers 513S that make up the brush may move in the direction indicated by arrow 10X. The fibers 513S may also move from the base side of the protrusion 521 towards the top side of the protrusion 521.

[0080] In this case, the deposits adhering to the belt member 510 become easier to detach from the belt member 510, making it easier to remove the deposits from the belt member 510. By providing the protrusion 521 on the belt member 510, the contact area between the belt member 510 and the paper P, which is a source of soiling, is reduced, and the number of areas to be cleaned is also reduced. Providing the protrusion 521 reduces the amount of dirt adhering to the belt member 510. In this case, compared to when there is a lot of dirt adhering to the belt member 510, uneven cleaning is less likely to occur.

[0081] Furthermore, providing the protrusion 521 reduces the load acting on the removal member 513 compared to when the protrusion 521 is not provided. In this case, the lifespan of the removal member 513 is extended. Let's consider a case where there is no protrusion 521 and cleaning is required over the entire surface of the belt member 510. In this case, the area of ​​the removal member 513 that is subjected to pressure from the belt member 510 becomes larger. In this case, the removal member 513 is more prone to deterioration. In contrast, providing the protrusion 521 reduces the load acting on the removal member 513 compared to the case where the protrusion 521 is not provided. In this case, the lifespan of the removal member 513 is extended.

[0082] Furthermore, by providing the protrusion 521 as in this embodiment, it becomes possible to position the removal member 513 further away from the belt member 510 compared to when the protrusion 521 is not provided. By providing the protrusion 521, the removal member 513 only needs to be brought into contact with the protrusion 521, making it possible to install the removal member 513 away from the belt member 510. In this case, the contact pressure between the removal member 513 and the belt member 510 decreases, extending the lifespan of the removal member 513.

[0083] Furthermore, as in this embodiment, if the protrusion 521 is positioned at an angle with respect to the belt movement direction, the contact time between the protrusion 521 and the removal member 513 becomes longer. Assume that the protrusion 521 is positioned along the direction of belt movement or in a direction perpendicular to the direction of belt movement. In this case, the contact time between the protrusion 521 and the removal member 513 is shortened as the protrusion 521 passes through. In contrast, in this embodiment, the protrusion 521 is positioned at an angle. In this case, the contact time between the protrusion 521 and the removal member 513 is increased as the protrusion 521 passes through the removal member 513. In this case, the reliability of removal of the adhering material by the removal member 513 is further increased.

[0084] However, this does not preclude the provision of the removal member 513 on the fixing device 60 side. A preferred embodiment is to provide the removal member 513 on the opposite side, but the removal member 513 may also be provided on the fixing device 60 side. For example, in an image forming apparatus 100 where the temperature of the fixing device 60 is low, the removal member 513 may be provided on the fixing device 60 side. Also, for example, if a member is provided to shield the heat moving from the fixing device 60 to the paper transport device 500, the removal member 513 may be provided on the fixing device 60 side.

[0085] 〔others〕 In the above explanation, we described an example in which the paper transport device 500 is located upstream of the fixing device 60 in the paper transport direction of the paper P. The paper transport device 500 may also be provided downstream of the fuser device 60. In this case, the paper P that has passed through the fuser device 60 is transported downstream by the paper transport device 500. Alternatively, the paper transport device 500 may be provided both upstream and downstream of the fixing device 60.

[0086] In a configuration where the paper transport device 500 is located downstream of the fixing device 60, the fixing device 60 is located upstream of the belt member 510 in the direction of transport of the paper P by the belt member 510. Even if the paper transport device 500 is installed downstream of the fuser device 60, the paper transport device 500 may still be affected by the heat from the fuser device 60, as described above. In this case as well, if the belt member 510 is provided with a protrusion 521 as described above, the occurrence of the above-mentioned problems caused by heat can be suppressed. Furthermore, if the paper transport device 500 is provided downstream of the fixing device 60, it is preferable to provide the removal member 513 on the opposite side from the fixing device 60, as described above.

[0087] Figures 11(A) and (B) show examples of other shapes of the protrusion 521. Figure 11 shows the cross-sectional state of the protrusion 521 in a plane perpendicular to the extension direction of the protrusion 521. The cross-sectional shape of the protruding portion 521 may be triangular, as shown in Figure 11(A), or trapezoidal, as shown in Figure 11(B). In the above, Figure 5 shows the cross-sectional shape of the protrusion 521. In Figure 5, the cross-sectional shape of the protrusion 521 was rectangular. The design is not limited to this; as shown in Figures 11(A) and (B), the cross-sectional shape of the protruding portion 521 may be triangular or trapezoidal.

[0088] As described above, the width W of the protrusion 521 is preferably 1.5 mm or less. Furthermore, the spacing between adjacent protrusions 521 is preferably 1.2 mm or more. Furthermore, as described above, it is preferable that the distance between the protrusions 521 be greater than or equal to the value obtained by multiplying the width W of the protrusion 521 by 0.8.

[0089] The case where the cross-sectional shape of the protruding portion 521 is triangular, as shown in Figure 11(A), will be explained. Hereinafter, in this specification, the distance between the apex and the base of this triangular projection 521 will be referred to as the total length 521Z. Furthermore, the portion of the projection 521 located one-quarter of the total length 521Z toward the base from the apex will be referred to as the intermediate portion 521K. Furthermore, we consider a hypothetical line segment 521S that passes through intermediate point 521K and extends in the width direction of the protruding portion 521. This line segment 521S has two ends S11, one end S1 and the other end S2.

[0090] If the cross-sectional shape of the protrusion 521 is triangular, it is preferable that the width W of the protrusion 521 at the intermediate point 521K be 1.5 mm or less. In other words, it is preferable that the length of the line segment 521S passing through the intermediate point 521K be 1.5 mm or less. If the cross-sectional shape of the protrusion 521 is triangular, the portion of the protrusion 521 located closer to the top than the intermediate portion 521K will be more likely to come into contact with the paper P. If the width W of the protruding portion 521 at intermediate point 521K is kept within 1.5 mm, then, as described above, uneven gloss will be less likely to occur.

[0091] Even when the cross-sectional shape of the protrusion 521 is triangular, it is preferable to set the distance between the protrusions 521 to 1.2 mm or more, as described above. Furthermore, if the cross-sectional shape of the protrusion 521 is triangular, it is preferable, as described above, to set the distance between the protrusions 521 to be greater than or equal to the value obtained by multiplying the width W of the protrusion 521 by 0.8.

[0092] Here, if the cross-sectional shape of the protrusion 521 is triangular, the distance between the protrusions 521 refers to the distance L11. The distance L11 is the distance between the line segments 521S that correspond to each of the protrusions 521. More specifically, the separation distance in this case refers to the distance between the end S11 of one line segment 521S corresponding to one protrusion 521 and the end S11 of another line segment 521S corresponding to another protrusion 521 located next to this one protrusion 521.

[0093] If the cross-sectional shape of the protruding portion 521 is triangular, it is preferable that the distance between the line segments 521S be 1.2 mm or more. Furthermore, if the cross-sectional shape of the projection 521 is triangular, it is preferable that the distance between the line segments 521S be greater than or equal to the value obtained by multiplying the width W of the projection 521 by 0.8. Here, the width W of the projection 521 refers to the width at the intermediate point 521K. In other words, here, the width W of the projection 521 refers to the length of the line segment 521S.

[0094] Furthermore, if the cross-sectional shape of the protruding portion 521 is trapezoidal as shown in Figure 9(B), it is preferable that the width W at the location where the upper surface 521J is located be 1.5 mm or less. Furthermore, even if the cross-sectional shape of the protrusion 521 is trapezoidal, it is preferable to set the distance between the protrusions 521 to 1.2 mm or more. Furthermore, it is preferable that this separation distance be greater than or equal to the value obtained by multiplying the width W of the protruding portion 521 by 0.8. Here, width W refers to the width of the protruding portion 521 at the location where the upper surface 521J is located.

[0095] If the cross-sectional shape of the protrusion 521 is trapezoidal, the distance between the protrusions 521 refers to the distance between the upper surfaces 521J of each adjacent protrusion 521. More specifically, the distance between the protrusions 521 refers to the distance between the ends 521M of each of the upper surfaces 521J. Each of the upper surfaces 521J has two ends 521M that are positioned differently from each other in the width direction of the protrusions 521. The distance between the protrusions 521 refers to the distance between the ends 521M of each of the upper surfaces 521J.

[0096] Figure 12 shows another example of the configuration of the belt member 510. Figure 12 shows a part of the belt member 510 as viewed from the front. In this configuration example, multiple independent annular projections 521 are provided. Each of the projections 521 is circular in shape. Furthermore, in this configuration example, a hole 522 is provided inside the protrusion 521.

[0097] In this example configuration, the area of ​​the hole 522 is smaller than the area of ​​the region enclosed by one of the protrusions 521. Note that the protrusion 521 is not limited to a circular shape; it may also be elliptical or rectangular. The protrusions 521 are not limited to being arranged in a grid pattern as described above; as shown in Figure 12, each of the multiple annular protrusions 521 may be provided independently. In this example configuration, a hole 522 is provided inside each of the protrusions 521.

[0098] "Independent state" refers to a state in which one protrusion 521 and another protrusion 521 located next to this one protrusion 521 are not in contact. It is not essential to provide a hole 522 corresponding to each of the protrusions 521. A configuration is possible in which holes 522 are provided corresponding to some of the protrusions 521, while holes 522 are not present on the inside of other protrusions 521. In this configuration example shown in Figure 12, the hole 522 is surrounded by the protrusion 521, increasing the adhesion force of the paper P to the belt member 510. In this configuration example shown in Figure 12, it is preferable to keep the width W of the protruding portion 521 within 1.5 mm, as described above.

[0099] (Note) (((1))) A belt member that performs circulating movement, having holes for allowing air to pass from the outer circumferential surface to the inner circumferential surface, and a belt member that transports a recording medium attached to the outer circumferential surface, The belt member is provided in a manner that it protrudes from the outer circumferential surface and is provided so as to surround the hole, A recording medium transport device equipped with the following features. (((2))) Multiple protrusions are provided and arranged in a grid pattern. The hole is surrounded by the projections located around the hole, among the multiple projections arranged in a grid pattern. A recording medium transport device as described in (((1))). (((3))) Each of the aforementioned protrusions, arranged in a grid pattern, is positioned at an inclination with respect to the direction of movement of the belt member. A recording medium transport device as described in (((2))). (((4))) Multiple annular protrusions are provided on the outer circumferential surface of the belt member, The area of ​​the hole is smaller than the area of ​​the region surrounded by one of the annular protrusions. A recording medium transport device as described in (((1))). (((5))) The aforementioned protrusion is provided in a linear shape, The width of the aforementioned protrusion is 1.5 mm or less. A recording medium transport device as described in any of (((1))) to (((4))). (((6))) Multiple protrusions are provided and arranged in a grid pattern. The distance between the adjacent protrusions that extend in a common direction is 1.2 mm or more. A recording medium transport device as described in (((5))). (((7))) Multiple protrusions are provided and arranged in a grid pattern. The distance between adjacent protrusions that extend in a common direction is greater than or equal to the value obtained by multiplying the width of the protrusion by 0.8. A recording medium transport device as described in any of (((1))) to (((6))). (((8))) Multiple protrusions are provided and arranged in a grid pattern. The hole is surrounded by the projections located around the hole, among the multiple projections arranged in a grid pattern. By arranging the aforementioned protrusions in a grid pattern, a plurality of rectangular protrusions are provided on the outer circumferential surface. The area of ​​the region enclosed by the rectangular protrusion is between 5% and 80% of the area of ​​the hole. A recording medium transport device as described in any of (((1))) to (((7))). (((9))) An image forming unit that forms an image on a recording medium, A heating device for heating the recording medium on which an image has been formed by the image forming unit, A recording medium transport device that transports a recording medium on which an image has been formed by the image forming unit to the heating device, or transports a recording medium that has passed through the heating device, Equipped with, An image forming apparatus in which the recording medium transport device has the configuration of the recording medium transport device described in any of (((1))) to (((8))).

[0100] According to the recording medium transport device described in (((1))), compared to a case where the protrusions protruding from the outer surface of the belt member do not surround the holes provided in the belt member, it is possible to suppress the reduction in the adhesion force of the recording medium to the outer surface of the belt member caused by providing protrusions on the outer surface of the belt member. In the recording medium transport device according to (((2))), compared to the case where the hole is captured by a single annular protrusion, multiple protrusions can be positioned on the airflow path that flows towards the hole along the surface of the recording medium that faces the belt member, thereby suppressing a decrease in suction force caused by air from outside the space between the belt member and the recording medium moving towards the hole. According to the recording medium transport device described in (((3))), the contact time between the member that contacts the outer surface of the belt member and the protrusion can be made longer when the member that contacts the outer surface of the belt member is provided, compared to when the protrusion is aligned with the direction of movement of the belt member or the width direction of the belt member. According to the recording medium transport device of (((4))), the attractive force acting on the recording medium, which is the attractive force acting per unit area, can be increased compared to the case where the area of ​​the hole is larger than the area of ​​the region surrounded by one annular protrusion. According to the recording medium transport device described in (((5))), gloss unevenness that may occur in the image formed on the recording medium can be reduced compared to the case where the width of the protruding part exceeds 1.5 mm. According to the recording medium transport device described in (((6))), the gloss unevenness that may occur in the image formed on the recording medium can be reduced compared to the case where the distance between adjacent protrusions is less than 1.2 mm. According to the recording medium transport device described in (((7))), the gloss unevenness that may occur in the image formed on the recording medium can be reduced compared to the case where the distance between the protrusions is less than the value obtained by multiplying the width of the protrusions by 0.8. According to the recording medium transport device of (((8))), the area of ​​the region surrounded by the protrusions can reduce gloss unevenness that may occur in the image formed on the recording medium compared to the case where the area of ​​the region surrounded by the protrusions is less than 5% of the area of ​​the hole, and the adhesion force of the recording medium to the belt member can be increased compared to the case where the area of ​​the region surrounded by the protrusions exceeds 80% of the area of ​​the hole. According to the image forming apparatus described in (((9))), compared to a case where the protrusions protruding from the outer surface of the belt member do not surround the holes provided in the belt member, it is possible to suppress the reduction in the adhesion force of the recording medium to the outer surface of the belt member caused by providing protrusions on the outer surface of the belt member. [Explanation of Symbols]

[0101] 60... Fixing device, 100... Image forming device, 120... Image forming section, 500... Paper transport device, 510... Belt member, 510A... Outer surface, 510B... Inner surface, 513... Removal member, 514... Driven rotating member, 515... Driven rotating member, 521... Protrusion, 521A... First protrusion, 521B... Second protrusion, 522... Hole, P... Paper

Claims

1. A belt member that performs circulating movement, having holes for allowing air to pass from the outer circumferential surface to the inner circumferential surface, and a belt member that transports a recording medium attached to the outer circumferential surface, The belt member is provided in a manner that it protrudes from the outer circumferential surface and is provided so as to surround the hole, A recording medium transport device equipped with the following features.

2. Multiple protrusions are provided and arranged in a grid pattern. The hole is surrounded by the projections located around the hole, among the multiple projections arranged in a grid pattern. A recording medium transport device according to claim 1.

3. Each of the aforementioned protrusions, arranged in a grid pattern, is positioned at an inclination with respect to the direction of movement of the belt member. The recording medium transport device according to claim 2.

4. Multiple annular protrusions are provided on the outer circumferential surface of the belt member, The area of ​​the hole is smaller than the area of ​​the region surrounded by one of the annular protrusions. A recording medium transport device according to claim 1.

5. The aforementioned protrusion is provided in a linear shape, The width of the aforementioned protrusion is 1.5 mm or less. A recording medium transport device according to claim 1.

6. Multiple protrusions are provided and arranged in a grid pattern. The distance between the adjacent protrusions that extend in a common direction is 1.2 mm or more. The recording medium transport device according to claim 5.

7. Multiple protrusions are provided and arranged in a grid pattern. The distance between adjacent protrusions that extend in a common direction is greater than or equal to the value obtained by multiplying the width of the protrusion by 0.

8. A recording medium transport device according to claim 1.

8. Multiple protrusions are provided and arranged in a grid pattern. The hole is surrounded by the projections located around the hole, among the multiple projections arranged in a grid pattern. By arranging the aforementioned protrusions in a grid pattern, a plurality of rectangular protrusions are provided on the outer circumferential surface. The area of ​​the region enclosed by the rectangular protrusion is between 5% and 80% of the area of ​​the hole. A recording medium transport device according to claim 1.

9. An image forming unit that forms an image on a recording medium, A heating device for heating the recording medium on which an image has been formed by the image forming unit, A recording medium transport device that transports a recording medium on which an image has been formed by the image forming unit to the heating device, or transports a recording medium that has passed through the heating device, Equipped with, An image forming apparatus wherein the recording medium transport device has the configuration of the recording medium transport device described in any one of claims 1 to 8.

Images